Electric circuit interrupter



Dec. 31, 1940. E. HARA i v ELECTRIC CIRCUIT INTERRUPTER Filed Dec. 20,1938 n 12 ////////U l////////il.//////7///\^/,\

Inventor-z El Har-el, if; JM His ttorneg Patented Dec. 31, 1940 UNITEDSTATES PATENT OFFICE ELECTRIC CIRCUIT INTERRUPTER Ei Hara, Yokohama,Japan, asilignorl to General Electric Company, a corporation of New YorkApplication December 20, 1938, Serial No. 246,882 In Japan February 26,1938 7 Claims.

My invention relates to electric circuit interrupters, more particularlyto those of the multiple break'type and has for its principal object theprovision of an improved circuit interrupter that is effective toutilize magnetic forces of the arc current for aiding arc interruptionat a plurality of breaks.

A more specific object of my invention is the provision of magneticblow-out means in a circuit interrupter of the character above referredto in combination with another arc extinguishing agent, such as a fluidor oil blast for example.

In accordance with my invention an arc interrupting device isconstituted of a plurality of spaced conductors so arranged as to beinterconnected adjacent the extremities thereof by sections of the arcthat is formed upon opening of the circuit. 'I'he conductors which arepreferably of arcuate or horseshoe shape estab.

lish with said arc sections an electric circuitl of generally helicalform so that the magnetic flux l produced 'by the helical circuit mayintersect said are sections to establish a magnetic blow-out action.

My invention will be more fully set forth in the following descriptionreferring to the accompanying drawing, and the features of novelty whichcharacterize my invention will be pointed out with particularity in'theclaims annexed to and forming a part of this specification.

Referring to the drawing, Fig. 1 is an elevational view, partly insection of an electric cir'- cuit breaker 'of the iiuid blast multiplebreak type embodying my invention; Fig. 2 is aplan view taken along thesectional line 2 2 of Fig. 1; and Fig. 3 is a detailed perspective -viewof part of the arcuate conductors shown in Fig. l for establishing withthe serially related arc sections a generally helical current path.

The' circuit breaker illustrated by Fig. l is of the so-called oil blasttype and comprises arc forming means such as separablel contactsincluding a ixed contact structure I and movable rod contact structure2. The fixed contact I includes spring-biased contact segments I' forcoating with the bifurcated end 2 of the rod contact. The contacts I and2 are suitably connected tc the breaker terminals, not shown.

The contacts are normally immersed in an arc extinguishing liquid, suchas oil, contained within the insulating casing 3. The casing 3 which isof a ceramic material such as porcelain, is closed (ci. zoo-15o)indicated at 5 through which the movable contact 2 operates. The arcextinguishing device comprises a pair of concentrically disposedinsulating cylinders 6 and 1, the inner cylinder 1. being supported by asleeve 1' and metallic plate 8 a predetermined distance from the baseplate 4 to form an arc chamber 9. The cylinder 1 is likewise spaced fromthe inner walls of the cylinder 6 to form venting passages Ill for thearc gases formed during circuit interruption.

For the purpose of providing multiple breaks within the interruptingdevice 5 and for interrupting the arcs at said breaks, there is provideda plurality of horseshoe-like conductors II, I2, I3, I4 and I5 spacedlongitudinally along the arc path, that is, the path of movement of themovable contact 2. As illustrated by Fig. 3, the spaced conductors arein superposed relation along and enclose the arc path so thatthe'discontinuous portions are staggered-with respect to oppositesidesvof the arc path. That is, the brokenaway portion of one arcuate orhorseshoe conductor is positioned above the continuous part of theconductor beneath the same. The arcuate conductors are positioned withinthe cylinder 1 by means of insulating spacing rings I6. It will,therefore, be apparent from the above description that as the arcinitially formed between the contacts I and 2 is lengthened, the arcwill transfer automatically to the closely adjacent conductors lalongthe side walls of the contact passage so that the arc is divided into anumber of serially related sections. That is, in the position shown, thearc sections will form progressively between fixed contact I andconducting plate 8, plate 8 to conductor II, conductor II to conductorI2,` and so on to the final section between conductor I5 and the contact2. For the purpose of insuring formation of the arc sections between theextremities of adjacent conductors so as to establish a substantiallyhelical composite path of arc sections and arcuate conductors for thearc current, the conductors as best illustrated by Fig. 3 are providedwith arcing portions or tips II', I2', and I3', etc. respectively, forshortening the arc path at those points. It will, therefore, be clearthat the arcuate conductors, when interconnected by the arc sections asdiagrammatically illustrated by Fig. 3, form a current path as indicatedby the directional arrows that is generally helical in form.Accordingly, the well-known magnetic loop effect that is inherent in acoil of helical shape tends to extend and blow out the serially relatedarc sections.

The magnetic blow-out eiect is preierably augmented by another arcextinguishing agentv such as an oil blast, and tol this end the cylinder1 is provided with pressure relief or exhaust ports I1 opposite therespective arcing tips il', etc. The insulating spacing rings i6 arealso cut away at IS' so as to register with the exhaust ports I1.Accordingly, as the arc is initially drawn at 9' within the chamber 9,the arc pressure established therein tends to blast the arc sections asthey are formed outwardly through the exhaust ports I1, asdiagrammatically illustrated. As each arc section is looped outwardly,the magnetic eiIect due to the helical circuit is furtherincreased sincethe upper and lower parts of the arc loop will both intersect the iluxproduced by the helical circuit. This in turn produces a twisting actionon the arc, diagrammatically illustrated at I8 in Fig. 3, which alsotends to extinguish the same in combination with the iluid blast. Theuid blast can obviously be created by piston means or the like and,therefore, need not be dependent on the arc energy.

It should be understood that my invention is not limited to speciiicdetails of construction and arrangment thereof herein illustrated, andthat changes and modicationsmay occur to one skilled in the art withoutdeparting from the spirit of my invention. For example, the arcdrawingmeans can obviously assume various forms. As an illustration, thearcuate conductors can be relatively movable so as to form the seriallyrelated arc sections above referred to independently of a movablecontact such as 2.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

l. In an electric circuit interrupter, means for forming an arc and aplurality oi' conductor? spaced along and around the longitudinal axisof said arc for dividing the same into sections, said conductors beingso arranged with respect to each other and said arc sections that thecomposite arc current path follows the form of s helix, said arcsections being at the outer side ofsaid helix whereby said arc sectionsare subjected to a magnetic blow-out in a direction substantiallytranversely of the longitudinal axis of said helix.

2. In an electric circuit interrupter, means for forming an arc and aplurality of arcuate conductors positioned between the extremities ai'and around said arc in superposed relation, said arcuate conductorsbeing -arranged to divide said arc into sections and to form with saidarc sections a substantially helical composite path for the arc currentwhereby said arc sections are subjected to magnetic forces of the arccurr-wt in a direction substantially transversely of the longitudinalaxis of said helix.

3. In an electric circuit interrupter, means for forming an arc and aplurality of arcuate conductors individually spaced along thelongitudinal axis of said arc so as substantially to surround said arcforming means, said conductors being insulated from each other andarranged to divide said arc into sections so as to form with said arcsections a substantially helical path for the arc current.

4. In an electric circuit interrupter, means for forming an arc and aplurality of arcuate conductors spaced along the longitudinal axis ofsaid arc, said arcuate conductors substantially surrounding said arcforming means and having the discontinuous portions thereof staggeredwith respect to opposite sides of said longitudinal axis, said arcforming means being arranged to transfer the arc to said arcuateconductors for dividing the arc into a plurality of sections wherebysaid sections form with said arcuate conductors a substantially helicalpath for utilizing for arc interruption magnetic forces of the arccurrent.

5. In an electric circuit breaker, separable contacts between which anarc is drawn upon opening ot the circuit. and a plurality of spacedarcuate conductors arranged to Iorm around the longitudinal axis of saidarc a discontinuous conducting path approaching the form of a helix,said arcuate conductors having arcing portions adjacentsaiddiscontinuous sections to which the arc is transferred by said separablecontacts for dividing said arc into a plurality of sections. said arcsections` forming with said arcuate conductors a composite path ofhelix-like forml for the arc current whereby said arc sections aresubjected to magnetic blow-out forces of the arc current in a directionsubstantially transversely of the longitudinal axis of said helix.

6. An electric circuit breaker comprising separable contacts. arc`interrupting structure assoelated with said contacts comprising aninsulating arc chamber in which the arc is drawn upon separation of saidcontacts, a plurality oi individual conductors disposed within saidcasing and adjacent the arc path so as to approach the form of a helixhaving a longitudinal axis substantially parallel to said arc path, saidconductors dividing the arc into a plurality of sections between saidconductors, said sections forming with said conductors a substantiallyhelical path for the arc current whereby said arc sections are subjectedto magnetic blow-out forces, said casing having openings adjacent saidarc sections respectively for permitting lateral extension o! theseparate arcs, and means for creating fluid pressure within said casingfor aiding extension of said separate arcs at said openings.

7. An electric circuit breaker comprising separable contacts, arcinterrupting structure associated with said contacts comprising a'ninsulating pressure coniining arc chamber. a plurality oi' arcuateconductors spaced in superposed relation along the arc path formed uponseparation of said contacts so as substantially to surround said arcpath, means for separating and insulating said arcuate conductors fromeach other, the discontinuous portions oi said arcuate conductors beingstaggered with respect to opposite sides of said arc path, arcing tipsconnected to said conductors at said discontinuous portions to which thearc is transferred from said contacts so that the arc is divided betweensaid conductors into a plurality of arc sections, pressure relief portsin said arc chamber opposite said arcing tips, said arc sections formingwith said conductors a path o generally helical form whereby magneticforces of the arc current tend to produce magnetic blow-out action atsaid arc sections, and means for creating huid pressure withinsaid ar'cchamber tending in addition to expel said arc sections through saidports.

EI HARA.

